As construction panels goods manufactured from colored sheets of stainless steel are widely used. Such a panel comprises a sheet of stainless steel having at least one surface, on which a rugged pattern may be optionally put, and a colored coat applied on said surface. The colored panel is used to cover surfaces of walls, pillars, ceilings, floors, doors, handrails, screens and other like parts of the interior and exterior of various buildings and other structures to impart them beautiful appearance and durability.
While decorative panels of stainless steel may be prepared so that they may have any arbitrary size, they normally have a surface area smaller than that of the surface to be covered by them. Namely, a surface of a large area is decorated by attaching thereon a plurality of adjacently arranged modular panels having a small surface area. To facilitate this attachment work each unit panel normally has one or more short bent portions formed along its side edges. Each bent portion usually comprises a side piece of a small width formed by bending the panel along its side approximately perpendicularly from the decorative surface to the back surface, and a flange piece formed by bending the front edge of the side piece at an angle of approximately 90.degree. so that the so formed flange piece is substantially parallel to the decorative surface. Such modular panels are secured on a surface to be decorated by laying a flange piece of one panel on that of another flange piece and fixing the overlapping flange pieces to the surface to be decorated by riveting or other fastening works. Thus, modular decorative panels of stainless steel normally have one or more bent portions where the panel is worked by bending it at an angle of approximately 90.degree. to ensure facilitation and stability of attachment of the panels to a surface to be decorated.
Decorative panels of stainless steel as a construction material have heretofore been prepared by a process in which a sheet of stainless steel is subjected to a chemical formation, painting or plating treatment to form a colored coat on the surface thereof, followed by a bending work as described above.